The idea of having spay and neuter procedures done early in a pet's life has become the rule with the uptick in pets being adopted from shelters and rescues, and one main reason behind it is certainly compelling: addressing the overpopulation problem.
There are other reasons that support the idea of having pets spayed and neutered early on. The reduction of the rates of some cancers in both species and sexes is touted, like mammary cancer in female cats. Longer life spans due to decreased risk of death from infectious diseases and trauma are also benefits.

Early spay and neuter procedures – in the case of shelters, very early — have seen their share of controversy in recent years as well, and the reasons why are frequently discussed in hushed tones in my midst at least a couple of times per month. I think that the fact that the topic getting attention at all is important.

One study conducted at UC Davis and published in February of 2013, included over 700 Golden Retrievers and found that males neutered before the age of 12 months were twice as likely to suffer from hip dysplasia, and that three times as many males who were neutered early had suffered from lymphosarcoma than their intact counterparts.

Female Rottweilers, according to research published in the 2009 issue of Aging Cell, who underwent spay procedures after the age of four were more likely to attain a longer life span, as opposed to females who were spayed at an earlier age.

Another study — this one by the Departments of Genetics and Small Animal Medicine and Surgery, University of Georgia, Athens – found that neutering (the more common, blanket term when referring to surgical sterilization of both sexes) was connected with an increased risk of death from cancer.

Most frequently, I'm hearing concerns about the uptick in orthopedic problems in many breeds of dog — mostly cranial cruciate ligament (CCL) tears – and the correlation between those and early neuter procedures.

Pet owners are not alone: Joint disorders are of particular interest to researchers as well.

We know that in mammals, puberty and sexual maturation is crucial in the development of the brain, bones and organs. Canines are of course, specific interest here.

Neutering removes the male dog's testes and the females ovaries, which interrupts production of some hormones that play key, often multiple, roles in important physiological processes – & with the closure of bone growth plates being one of them.

The UC study showed that there was an increase in CCL cases in both male and female dogs who had been surgically sterilized. (There were no cases of CCL injuries in dogs who were intact.)

To be practical, the uptick in joint diseases among these dogs is likely due to a combination of things, like the effect of neutering on the young dog’s growth plates, but also the additional weight on the joints that is associated with neutered dogs.

Chris Zink, DVM, a noted canine sports expert has asserted that we might consider the repercussions of neuter procedures that are done before a pet has a chance to fully develop.

With all of this information and ongoing discussion, it seems prudent to remember that we need to be careful how we extrapolate, examine and use this kind of data when it comes to the health and behavior of pets – and how we make decisions about when and why to neuter them, not to mention what has fueled the practice